One or more aspects relate, in general, to coordinated timing networks, and in particular, to merging coordinated timing networks.
A Coordinated Timing Network (CTN) is a network in which multiple distinct computing systems maintain time synchronization to form the coordinated timing network. Systems in the coordinated timing network employ a message based protocol, referred to as a Server Time Protocol (STP), to pass timekeeping information between the systems over existing, high-speed data links. This enables the time of day (TOD) clocks at each system to be synchronized to the accuracy required in today's high-end computing systems. Since the protocol makes use of technology within a computing system, synchronization accuracy scales as technology improves. A computing system that provides time to other computing systems is referred to as a time server or server herein.
Within a coordinated timing network for STP, there is to be only one server acting as the source of time for the network (referred to as the primary time server). If there is more than one time source, the two sources could diverge leading to a data integrity exposure. Likewise, if there is no single server acting as the source of time for the network, the clocks on the multiple servers could drift apart, raising a data integrity exposure in that way.
Customers using the Server Time Protocol have encountered situations in which multiple coordinated timing networks are to be merged into a single coordinated timing network. However, to accomplish this, one or more of the servers needs to be brought down. This is very disruptive to the customers' business and usually means a loss of business and revenue.